内容摘要：行政诉讼第三人是行政诉讼中的一项重要制度，是具有理论意义和实践意义的课题。我国行政诉讼领域对第三人制度的研究起步较晚，相比其他各国、各地区的行政诉讼第三人体系，我国的立法较为匮乏且倾向于原则性抽象性。同时由于理论研究的不完善，在行政诉讼领域内我国至今未建立起一个自洽的理论体系，本文从法条中的“利害关系”为着眼点，提出了行政诉讼第三人适格的三个要件，围绕此，探讨了法律实践中多种情形的判定和区分。

关键词：行政诉讼、行政诉讼第三人、利害关系

Abstract: The third party in administrative litigation is an important system in administrative litigation, which is of great importance both in theory and practice. The research in the third party in the field of  administrative litigation started late in china ,compared to the third party system in other regions and other countries , our law legislation is  tend to be more principle and abstract . Because of  the inadequacy of the theoretical research , we haven’t build a self –consistent theoretical system in the field administrative litigation in china till now .This essay focus on the key word ”stake” and put forward three key elements of  qualified  third party in administrative litigation  Centering on this focal point  ,this paper will analyses  how to judge and distinguish different  situations in practice.

Key words: The administrative litigation ，The third party in administrative litigation, Third person qualification